Network requested packet data protocol context activation

ABSTRACT

A packet switched (PS) core network (CN) supporting several quality of services levels, comprising at least a serving node (SGSN), a gateway node (GGSN), a home location register (HLR), a short message service gateway and interworking unit (SMS-GMSC, SMS-IWMSC), charging gateway functionality (CGF), and a public data network (PDN) comprising an application server (AS). The core network is adapted for carrying out a packet data protocol (PDP) context activation in which a PDP address is assigned to a mobile station and in which a given quality of service is assigned through the network in a communication session between the mobile station and the application processor in question, whereby the application server (AS) initiates a context activation in which the QoS is seeked altered for the mobile station.

FIELD OF THE INVENTION

[0001] The present invention relates to a method for a packet data andtelecommunication systems, comprising wireless and wirelinesub-networks. The invention concerns in particular a method for a PDP(Packet Data Protocol) context activation procedure in a core networkbased on GSM (Global System for Mobile telephony), GPRS (General Packetradio System) and UMTS (Universal Mobile Telephony System) elements.

BACKGROUND OF THE INVENTION

[0002] According to the 3'rd generation partnership project (3GPP)technical specification, 3G TS 23.060 v3.4.0 (2000-07) a common packetdomain Core Network is used for both GSM and UMTS. Such a system hasbeen shown in FIG. 1. A similar system has been shown in WO99/05828.

[0003] The above Core Network provides packet-switched (PS) services andis designed to support several quality of services levels in order toallow efficient transfer of non real-time traffic (e.g., intermittentand bursty data transfers, occasional transmission of large volumes ofdata) and real-time traffic (e.g., voice, video). One class of qualityof service pertains to a low throughput and a low delay; another classpertains to higher throughput and longer delay and a further classpertains to relatively long delays and high throughput.

[0004] Applications based on standard data protocols and SMS aresupported, and interworking is defined with IP networks. Charging isrendered flexible and allows Internet Service Providers to billaccording to the amount of data transferred, the QoS supported, and theduration of the connection.

[0005] Each PLMN has two access points, the radio interface (labelled Umin GSM and Uu in UMTS) used for mobile access and the R reference pointused for origination or reception of messages.

[0006] An interface differs from a reference point in that an interfaceis defined where specific information is exchanged and needs to be fullyrecognised. There is an inter PLMN interface called Gp that connects twoindependent packet domain networks for message exchange. There is also aPLMN to fixed network (typically a packet data network) reference pointcalled Gi.

[0007] There may be more than a single network interface to severaldifferent packet data (or other) networks. These networks may bothdiffer in ownership as well as in communications protocol (e.g., TCP/IPetc.). The network operator should define and negotiate interconnectwith each external (PDN or other) network.

[0008] Network interworking is required whenever a packet domain PLMNand any other network are involved in the execution of a servicerequest. With reference to FIG. 1, interworking takes place through theGi reference point and the Gp interface.

[0009] The internal mechanism for conveying the PDP (Packet DataProtocol) PDU (Packet Data Unit) through the PLMN is managed by the PLMNnetwork operator and is not apparent to the data user. The use of thepacket domain data service may have an impact on and increase thetransfer time normally found for a message when communicated through afixed packet data network.

[0010] The packet domain supports interworking with networks based onthe Internet protocol (IP). The packet domain may provide compression ofthe TCP/IP header when an IP datagram is used within the context of aTCP connection.

[0011] The packet domain PLMN service is an IP domain, and mobileterminals offered service by a service provider may be globallyaddressable through the network operator's addressing scheme.

[0012] A GPRS Support Node (GSN) contains functionality required tosupport GPRS functionality for GSM and/or UMTS. In one PLMN, there maybe more than one GSN.

[0013] The Gateway GPRS Support Node (GGSN) is the node that is accessedby the packet data network due to evaluation of the PDP address. Itcontains routing information for PS-attached users. The routinginformation is used to tunnel N-PDUs to the MS's current point ofattachment, i.e., the Serving GPRS Support Node. The GGSN may requestlocation information from the HLR via the optional Gc interface. TheGGSN is the first point of PDN interconnection with a GSM PLMNsupporting GPRS (i.e., the Gi reference point is supported by the GGSN).GGSN functionality is common for GSM and UMTS.

[0014] The Serving GPRS Support Node (SGSN) is the node that is servingthe MS. The SGSN supports GPRS for GSM (i.e., the Gb interface issupported by the SGSN) and/or UMTS (i.e., the lu interface is supportedby the SGSN).

[0015] In order to access the PS services, an MS shall first make itspresence known to the network by performing a GPRS Attach. This makesthe MS available for SMS over PS, paging via the SGSN, and notificationof incoming PS data. According to the Attach, the IMSI (InternationalMobile Subscription Identity) of the mobile station (MS) is mapped toone or more packet data protocol addresses (PDP).

[0016] At PS Attach, the SGSN establishes a mobility management contextcontaining information pertaining to e.g., mobility and security for theMS.

[0017] In order to send and receive PS data, the MS shall activate thePacket Data Protocol context that it wants to use. This operation makesthe MS known in the corresponding GGSN, and interworking with externaldata networks can commence.

[0018] At PDP Context Activation, the SGSN establishes a PDP context, tobe used for routing purposes, with the GGSN that the subscriber will beusing.

[0019] The SGSN and GGSN functionalities may be combined in the samephysical node, or they may reside in different physical nodes. SGSN andGGSN contain IP or other (operator's selection, e.g., ATM-SVC) routingfunctionality, and they may be interconnected with IP routers. In UMTS,the SGSN and RNC may be interconnected with one or more IP routers. WhenSGSN and GGSN are in different PLMNs, they are interconnected via the Gpinterface. The Gp interface provides the functionality of the Gninterface, plus security functionality required for inter-PLMNcommunication. The security functionality is based on mutual agreementsbetween operators.

[0020] The SGSN may send location information to the MSC/VLR via theoptional Gs interface. The SGSN may receive paging requests from theMSC/VLR via the Gs interface.

[0021] According to the PDP context activation, a network bearer (IP)communication between the mobile station and the Internet serviceprovider (ISP) is established. Moreover, a given class of Quality ofService class is assigned for the communication to be performed.

[0022] The Charging Gateway Functionality (CGF) collects chargingrecords from SGSNs and GGSNs. The HLR (Home Location Register) containsGSM and UMTS subscriber information. The HLR stores the IMSI(International Mobile Subscription Identity) and maps the IMSI to one ormore packet data protocol addresses (PDP) and maps each PDP address toone or more GGSN's.

[0023] The SMS-GMSCs and SMS-IWMSCs support SMS transmission via theSGSN. Optionally, the MSC/VLR can be enhanced for more-efficientco-ordination of packet-switched and circuit-switched services andfunctionality: e.g., combined GPRS and non-GPRS location updates.

[0024] User data is transferred transparently between the MS and theexternal data networks with a method known as encapsulation andtunnelling: data packets are equipped with PS-specific protocolinformation and transferred between the MS and the GGSN. Thistransparent transfer method lessens the requirement for the PLMN tointerpret external data protocols, and it enables easy introduction ofadditional interworking protocols in the future.

[0025] An Application Server (AS) is connected to the Packet DataNetwork (PDN) for providing information. The application server may beowned by an Internet Service Provider (ISP), the PLMN, or an independentcompany.

[0026] MS Initiated PDP Context Activation

[0027] We shall now revert to the PDP context activation procedure.

[0028] In FIG. 2, a sequence diagram relating to the Mobile Stationinitiated context activation procedure has been shown.

[0029] 1) The MS sends an Activate PDP Context Request (NSAPI, TI, PDPType, PDP Address, Access Point Name, QoS Requested, PDP ConfigurationOptions) message to the SGSN. The MS may use Access Point Name to selecta reference point to a certain external network and/or to select aservice. QoS Requested indicates the desired QoS profile.

[0030] 3) In UMTS, RAB (Radio Bearer) set-up is done by the RABAssignment procedure.

[0031] 4) If BSS trace is activated, then the SGSN shall send an InvokeTrace (Trace Reference, Trace Type, Trigger Id) message to the BSS orUTRAN. Trace Reference and Trace Type are copied from the traceinformation received from the HLR. Thereby, the location of the mobilestation can be established.

[0032] 5a) The SGSN validates the Activate PDP Context Request using PDPType (optional), PDP Address (optional), and Access Point Name(optional) provided by the MS and the PDP context subscription records

[0033] The SGSN may restrict the requested QoS attributes given itscapabilities, the current load, and the subscribed QoS profile.

[0034] The SGSN sends a Create PDP Context Request (PDP Type, PDPAddress, Access Point Name, QoS Negotiated, TEID, NSAPI, MSISDN,Selection Mode, Charging Characteristics, Trace Reference, Trace Type,Trigger Id, PDP Configuration Options) message to the affected GGSN

[0035] 5b) The GGSN creates a new entry in its PDP context table andgenerates a Charging Id. The new entry allows the GGSN to route PDP PDUsbetween the SGSN and the external PDP network, and to start charging.The GGSN then returns a Create PDP Context Response (TEID, PDP Address,PDP Configuration Options, QoS Negotiated, Charging Id, Cause) messageto the SGSN.

[0036] 6) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns an Activate PDP Context Accept (PDP Type,PDP Address, TI, QoS Negotiated, Radio Priority, Packet Flow Id, PDPConfiguration Options) message to the MS. The SGSN is now able to routePDP PDUs between the GGSN and the MS, and to start charging.

[0037] 7) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0038] For each PDP Address, a different quality of service (QoS)profile may be requested. For example, some PDP addresses may beassociated with E-mail that can tolerate lengthy response times. Otherapplications cannot tolerate delay and demand a very high level ofthroughput, interactive applications being one example. These differentrequirements are reflected in the QoS profile. If a QoS QoS profilerequirement is beyond the capabilities of a PLMN, the PLMN negotiatesthe QoS profile as close as possible to the requested QoS profile. TheMS either accepts the negotiated QoS profile, or deactivates the PDPcontext.

[0039] AS Initiated PDP Context Activation

[0040] The scenario for setting up a session initiated by the anexternal application server has been illustrated by the sequence diagramshown in FIG. 3:

[0041] The Network-Requested PDP Context Activation procedure allows theGGSN to initiate the activation of a PDP context. When receiving a PDPPDU the GGSN checks if a PDP context is established for that PDPaddress. If no PDP context has been previously established the GGSN maytry to deliver the PDP PDU by initiating the Network-Requested PDPContext Activation procedure.

[0042] 1) When receiving a PDP PDU the GGSN determines if theNetwork-Requested PDP Context Activation procedure has to be initiated.The GGSN may store subsequent PDP PDU's received for the same PDPaddress.

[0043] 2a) The GGSN may send a Send Routing Information for GPRS (IMSI)message to the HLR.

[0044] 2b) If the HLR determines that the request can be served, itreturns a Send Routing Information for GPRS Ack (IMSI, SGSN Address,Mobile Station Not Reachable Reason) message to the GGSN.

[0045] 3a) The GGSN shall send a PDU Notification Request (IMSI, PDPType, PDP Address, APN) message to the SGSN indicated by the HLR.

[0046] 3b)The SGSN returns a PDU Notification Response (Cause) messageto the GGSN in order to acknowledge that it shall request the MS toactivate the PDP context indicated with PDP Address.

[0047] 4) The SGSN sends a Request PDP Context Activation (TI, PDP Type,PDP Address, APN) message to request the MS to activate the indicatedPDP context.

[0048] 5) The PDP context is activated with the PDP Context Activationprocedure.

[0049] As mentioned above, it is possible that the mobile station needsa different QoS from what was initially needed. In order to modify theQoS, the mobile station may take one of the following steps:

[0050] The MS initiates a new primary PDP Context.

[0051] There is an active PDP context, but it is established withinsufficient bandwidth, QoS. The MS may trigger a PDP ContextModification.

[0052] There is an active PDP context, but it is established withinsufficient bandwidth, QoS. The MS may trigger a secondary PDP ContextModification.

[0053] The two latter procedures shall be dealt with below.

[0054] In FIG. 4, a procedure of the mobile station modifying the PDPcontext is shown in which the following steps are carried out:

[0055] 1) The MS sends a Modify PDP Context Request (TI, QoS Requested,TFT) message to the SGSN. Either QoS Requested or TFT or both may beincluded. QoS Requested indicates the desired QoS profile, while TFTindicates the TFT that is to be added or modified or deleted from thePDP context.

[0056] 2) The SGSN may restrict the desired QoS profile given itscapabilities, the current load, and the subscribed QoS profile. The SGSNsends an Update PDP Context Request (TEID, NSAPI, QoS Negotiated, TFT)message to the GGSN. If QoS Negotiated and/or TFT received from the SGSNis incompatible with the PDP context being modified (e.g., TFT containsinconsistent packet filters), then the GGSN rejects the Update PDPContext Request. The compatible QoS profiles are configured by the GGSNoperator.

[0057] 3) The GGSN may further restrict QoS Negotiated given itscapabilities and the current load. The GGSN stores QoS Negotiated,stores, modifies, or deletes TFT of that PDP context as indicated inTFT, and returns an Update PDP Context Response (TEID, QoS Negotiated)message.

[0058] 4) In UMTS, radio access bearer modification may be performed bythe RAB Assignment procedure.

[0059] 5) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns a Modify PDP Context Accept (TI, QoSNegotiated, Radio Priority, Packet Flow Id) message to the MS.

[0060] In FIG. 5, a procedure for activation of a secondary PDP contexthas been shown in which the following steps are carried out:

[0061] 1) The MS sends an Activate Secondary PDP Context Request (LinkedTI, NSAPI, TI, QoS Requested, TFT) message to the SGSN. Linked TIindicates the TI value assigned to any one of the already activated PDPcontexts for this PDP address and APN. QoS Requested indicates thedesired QoS profile. TFT is sent transparently through the SGSN to theGGSN to enable packet classification for downlink data transfer. TI andNSAPI contain values not used by any other activated PDP context.

[0062] 2) In GSM, security functions may be executed.

[0063] 3) In UMTS, RAB set-up is done by the RAB Assignment procedure.

[0064] 4a) The SGSN validates the Activate Secondary PDP Context Requestusing the TI indicated by Linked TI. The same GGSN address is used bythe SGSN as for the already-activated PDP context(s) for that TI and PDPaddress.

[0065] The SGSN and GGSN may restrict and negotiate the requested QoS.The SGSN sends a Create PDP Context Request (QoS Negotiated, TEID,NSAPI, Primary NSAPI, TFT) message to the affected GGSN. Primary NSAPIindicates the NSAPI value assigned to any one of the already activatedPDP contexts for this PDP address and APN. TFT is included only ifreceived in the Activate Secondary PDP Context Request message. The GGSNuses the same external network as used by the already-activated PDPcontext(s) for that PDP address, generates a new entry in its PDPcontext table, and stores the TFT. The new entry allows the GGSN toroute PDP PDUs via different GTP tunnels between the SGSN and theexternal PDP network.

[0066] 4b) The GGSN returns a Create PDP Context Response (TEID, QoSNegotiated, Cause) message to the SGSN.

[0067] In GSM, BSS packet flow context procedures may be executed.

[0068] 5) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns an Activate Secondary PDP Context Accept(TI, QoS Negotiated, Radio Priority, Packet Flow Id) message to the MS.The SGSN is now able to route PDP PDUs between the GGSN and the MS viadifferent GTP tunnels and possibly different LLC links.

[0069] Push Services

[0070] One type of service which can be accomplished in the above systemis so-called “push” services, that is, an Application Server (AS) takesthe initiative to render information, such as stock quotes, news orcommercials, available to one or a plurality of mobile terminals.

SUMMARY OF THE INVENTION

[0071] It is a first object of the present invention to set forth amethod for effectively assigning a given quality of service to a serverinitiated communication session.

[0072] This object has been accomplished by the subject matter set forthin claim α1.

[0073] Further advantages will appear from the following detaileddescription and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0074]FIG. 1 shows a prior art common packet domain core network for GSMand UMTS use,

[0075]FIG. 2 discloses a sequence diagram for a known context activationprocedure initiated by a mobile station,

[0076]FIG. 3 discloses a sequence diagram for a known context activationprocedure initiated by an application server,

[0077]FIG. 4 discloses a sequence diagram for a known procedureinitiated by the mobile station for modifying the PDP context,

[0078]FIG. 5 discloses a sequence diagram for a known procedureinitiated by the mobile station for a secondary modification of the PDPcontext,

[0079]FIG. 6 discloses a sequence diagram for a first embodiment of acontext activation procedure initiated by an application serveraccording to the invention. The MS is contacted with an SMS message,including the QoS(R), which in turn triggers the MS to start the PDPContext Activation procedure,

[0080]FIG. 7 discloses a sequence diagram for a second embodiment of acontext activation procedure initiated by an application serveraccording to the invention. The GGSN receives a push request, includingthe QoS(R), from the AS,

[0081]FIG. 8 discloses a sequence diagram for a third embodiment of acontext activation procedure initiated by an application serveraccording to the invention. The GGSN receives an incoming PDU from whichthe GGSN can deduce the QoS(R) (e.g., mapping of the ds-byte of theIP-header to the defined corresponding QoS(R)),

[0082]FIG. 9 discloses a sequence diagram for a fourth embodiment of acontext activation procedure initiated by an application serveraccording to the invention. The MS is contacted with an SMS message,including the QoS(R). The MS chooses to trigger the PDP ContextModification procedure, and

[0083]FIG. 10 discloses a sequence diagram for a fifth embodiment of acontext activation procedure initiated by an application serveraccording to the invention. The MS is contacted with an SMS message,including the QoS(R). The MS chooses to initiate a secondary PDPContext.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0084] First Embodiment

[0085] The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the MS (by SMS), is illustrated by the sequencediagram shown in FIG. 6:

[0086] 1) A push request is sent to the MS through an SMS message,asking for a session with a certain QoS, the QoS(R). The MS does nothave an active PDP Context. Delivery of the SMS involves the nodes SC,SMS-GMSC, HLR and SGSN.

[0087] 2) The MS sends an Activate PDP Context Request (NSAPI, TI, PDPType, PDP Address, Access Point Name, QoS Requested, PDP ConfigurationOptions) message to the SGSN. The MS may use Access Point Name to selecta reference point to a certain external network and/or to select aservice. QoS Requested indicates the desired QoS profile.

[0088] 3) In UMTS, RAB (Radio Bearer) set-up is done by the RABAssignment procedure.

[0089] 4) If BSS trace is activated, then the SGSN shall send an InvokeTrace (Trace Reference, Trace Type, Trigger Id, OMC Identity) message tothe BSS or UTRAN. Trace Reference, and Trace Type are copied from thetrace information received from the HLR or OMC.

[0090] 5a) The SGSN validates the Activate PDP Context Request using PDPType (optional), PDP Address (optional), and Access Point Name(optional) provided by the MS and the PDP context subscription records

[0091] The SGSN may restrict the requested QoS attributes given itscapabilities the current load, and the subscribed QoS profile.

[0092] The SGSN sends a Create PDP Context Request (PDP Type, PDPAddress, Access Point Name, QoS Negotiated, TEID, NSAPI, MSISDN,Selection Mode, Charging Characteristics, Trace Reference, Trace Type,Trigger Id, OMC Identity, PDP Configuration Options) message to theaffected GGSN

[0093] The GGSN creates a new entry in its PDP context table andgenerates a Charging Id. The new entry allows the GGSN to route PDP PDUsbetween the SGSN and the external PDP network, and to start charging.

[0094] 5b) The GGSN then returns a Create PDP Context Response (TEID,PDP Address, PDP Configuration Options, QoS Negotiated, Charging Id,Cause) message to the SGSN.

[0095] 6) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns an Activate PDP Context Accept (PDP Type,PDP Address, TI, QoS Negotiated, Radio Priority, Packet Flow Id, PDPConfiguration Options) message to the MS. The SGSN is now able to routePDP PDUs between the GGSN and the MS, and to start charging.

[0096] 7) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0097] It follows from the above procedure, that the service of qualityrequested by the application server is communicated in the initialrequest towards the mobile station.

[0098] Second Embodiment

[0099] The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the GGSN (by some protocol), is illustrated by thesequence diagram shown in FIG. 7 (only the new points are mentionedhere)

[0100] 1) The AS sends a push request to the GGSN, asking the GGSN tolocated the MS and request it to activate a PDP context with a certainQoS, the QoS(R).

[0101] 2a) The GGSN may send a Send Routing Information for GPRS (IMSI)message to the HLR.

[0102] 2b) If the HLR determines that the request can be served, itreturns a Send Routing Information for GPRS Ack (IMSI, SGSN Address,Mobile Station Not Reachable Reason) message to the GGSN.

[0103]3a) The GGSN shall send a PDU Notification Request (IMSI, PDPType, PDP Address, APN, QoS(R)) message to the SGSN indicated by theHLR.

[0104] 3b) The SGSN responds with PDU Notification.

[0105] 4) The SGSN sends a Request PDP Context Activation (TI, PDP Type,PDP Address, APN, QoS(R)) message to request the MS to activate theindicated PDP context.

[0106] 5) PDP Context Activation as in FIG. 2.

[0107] 6) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0108] Third Embodiment

[0109] The scenario for setting up a session initiated by an externalapplication server, when QoS is deduced from the incoming PDP PDU sentfrom the AS to the GGSN, is illustrated by the sequence diagram shown inFIG. 8.

[0110] 1) A PDP PDU is received in the GGSN. The GGSN reads the QoSinformation in the packet, e.g., the ds-byte of the IP header (shown inthe figure), and maps it to the appropriate QoS(R).

[0111] 2a) The GGSN may send a Send Routing Information for GPRS (IMSI)message to the HLR.

[0112] 2b) If the HLR determines that the request can be served, itreturns a Send Routing Information for GPRS Ack (IMSI, SGSN Address,Mobile Station Not Reachable Reason) message to the GGSN.

[0113] 3a) The GGSN shall send a PDU Notification Request (IMSI, PDPType, PDP Address, APN, QoS(R)) message to the SGSN indicated by theHLR.

[0114] 3b) The SGSN responds with PDU Notification.

[0115] 4) The SGSN sends a Request PDP Context Activation (TI, PDP Type,PDP Address, APN, QoS(R)) message to request the MS to activate theindicated PDP context.

[0116] 5) PDP Context Activation as in FIG. 2.

[0117] 6) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0118] Fourth Embodiment

[0119] The scenario for modifying an active session, initiated by anexternal application server, when QoS has been included in thecommunication between the AS and the MS (by SMS), is illustrated by thesequence diagram shown in FIG. 9:

[0120] 1) A push request is sent to the MS through an SMS message,asking for a session with a certain QoS, the QoS(R). The MS has anactive PDP Context associated with a QoS class. Delivery of the SMSinvolves the nodes SC, SMS-GMSC, HLR and SGSN.

[0121] 2) If the QoS of the active PDP Context is not sufficient, the MSmay send a Modify PDP Context Request (TI, QoS Requested, TFT) messageto the SGSN. Either QoS Requested or TFT or both may be included. QoSRequested indicates the desired QoS profile, while TFT indicates the TFTthat is to be added, modified, or deleted from the PDP context.

[0122] 3) The SGSN may restrict the desired QoS profile given itscapabilities, the current load, and the subscribed QoS profile. The SGSNsends an Update PDP Context Request (TEID, NSAPI, QoS Negotiated, TFT)message to the GGSN. If QoS Negotiated and/or TFT received from the SGSNis incompatible with the PDP context being modified (e.g., TFT containsinconsistent packet filters), then the GGSN rejects the Update PDPContext Request. The compatible QoS profiles are configured by the GGSNoperator.

[0123] 4) The GGSN may further restrict QoS Negotiated given itscapabilities and the current load. The GGSN stores QoS Negotiated,stores, modifies, or deletes TFT of that PDP context as indicated inTFT, and returns an Update PDP Context Response (TEID, QoS Negotiated)message.

[0124] 5) In UMTS, radio access bearer modification may be performed bythe RAB Assignment procedure.

[0125] 6) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns a Modify PDP Context Accept (TI, QoSNegotiated, Radio Priority, Packet Flow Id) message to the MS.

[0126] 7) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0127] Fifth Embodiment

[0128] The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the MS (by SMS), is illustrated by the sequencediagram shown in FIG. 10:

[0129] 1) A push request is sent to the MS through an SMS message,asking for a session with a certain QoS, the QoS(R). The MS has anactive PDP Context associated with a QoS class. Delivery of the SMSinvolves the nodes SC, SMS-GMSC, HLR and SGSN.

[0130] 2) If the QoS of the active PDP Context is not sufficient, the MSmay send an Activate Secondary PDP Context Request (Linked TI, NSAPI,TI, QoS Requested, TFT) message to the SGSN. Linked TI indicates the TIvalue assigned to any one of the already activated PDP contexts for thisPDP address and APN. QoS Requested indicates the desired QoS profile.TFT is sent transparently through the SGSN to the GGSN to enable packetclassification for downlink data transfer. TI and NSAPI contain valuesnot used by any other activated PDP context.

[0131] In GSM, security functions may be executed.

[0132] 3) In UMTS, RAB set-up is done by the RAB Assignment procedure.

[0133] 4a) The SGSN validates the Activate Secondary PDP Context Requestusing the TI indicated by Linked TI. The same GGSN address is used bythe SGSN as for the already-activated PDP context(s) for that TI and PDPaddress.

[0134] The SGSN and GGSN may restrict and negotiate the requested QoS.The SGSN sends a Create PDP Context Request (QoS Negotiated, TEID,NSAPI, Primary NSAPI, TFT) message to the affected GGSN. Primary NSAPIindicates the NSAPI value assigned to any one of the already activatedPDP contexts for this PDP address and APN. TFT is included only ifreceived in the Activate Secondary PDP Context Request message. The GGSNuses the same external network as used by the already-activated PDPcontext(s) for that PDP address, generates a new entry in its PDPcontext table, and stores the TFT. The new entry allows the GGSN toroute PDP PDUs via different GTP tunnels between the SGSN and theexternal PDP network.

[0135] 4b) The GGSN returns a Create PDP Context Response (TEID, QoSNegotiated, Cause) message to the SGSN.

[0136] In GSM, BSS packet flow context procedures may be executed.

[0137] 5) The SGSN selects Radio Priority and Packet Flow Id based onQoS Negotiated, and returns an Activate Secondary PDP Context Accept(TI, QoS Negotiated, Radio Priority, Packet Flow Id) message to the MS.The SGSN is now able to route PDP PDUs between the GGSN and the MS viadifferent GTP tunnels and possibly different LLC links.

[0138] 6) Now, a packet data session is open between the Mobile Station(MS) and the Application Server (AS).

[0139] As appears from the above exemplary embodiments, the inventionprovides for a number of advantages.

[0140] By making it possible to send the requested QoS class inconnection with the Network Requested PDP Context process, theestablishment of a PDP session with an appropriate bandwidth/reliabilityis facilitated. A possible PDP Context Modification procedure in directconnection to the PDP session initiation is avoided, thus decreasing theamount of signalling required for the Network Requested PDP ContextActivation procedure.

[0141] According to invention, the Mobile Station (MS) is given anopportunity to choose to set up an appropriate session. This willpositively affect at least the network and the mobile stationcapabilities. Hence, procedures that are more flexible can be built intothe mobile station. Abbreviations AS Application Server APN Access PointName ATM Asynchronous Transfer Mode ATM-SVC ATM-Switched Virtual CircuitBSS Base Station System CGF Charging Gateway Functionality GGSN GatewayGPRS Serving Node GPRS General Packet Radio System GSM Global System forMobile telephony HLR Home Location Register IMSI International MobileSubscriber Identity IP Internet Protocol MS Mobile Station MSC-VLRMobile Switching Centre MSISDN MS International ISDN Number NSAPINetwork layer Service Access Point Identifier PDN Packet Data NetworkPDP Packet Data Protocol, e.g., IP PDU Protocol Data Unit PLMN PublicLand Mobile Network PS Packet Switched QoS Quality of Service RAB RadioAccess Bearer SGSN Serving GPRS Support Node SM Short Message SMS ShortMessage Service SM-SC Short Message Service Centre SMS-GMSC ShortMessage Service Gateway MSC SMS-IWMSC Short Message Service InterworkingMSC TCP Transmission Control Protocol TE Terminal Equipment TEID TunnelEndpoint IDentifier TI Transaction Identifier UMTS Universal MobileTelephony System UTRAN UMTS Terrestrial Radio Access Network Ga Chargingdata collection interface between a CDR transmitting unit (e.g., an SGSNor a GGSN) and a CDR receiving functionality (a CGF). Gb Interfacebetween an SGSN and a BSS. Gc Interface between a GGSN and an HLR. GdInterface between a SMS-GMSC and an SGSN, and between a SMS-IWMSC and anSGSN. Gf Interface between an SGSN and an EIR. Gi Reference pointbetween GPRS and an external packet data network. Gn Interface betweentwo GSNs within the same PLMN. Gp Interface between two GSNs indifferent PLMNs. The Gp interface allows support of GPRS networkservices across areas served by the co- operating GPRS PLMNs. GrInterface between an SGSN and an HLR. Gs Interface between an SGSN andan MSC/VLR. lu Interface between the RNS and the core network. It isaiso considered as a reference point. R Reference point between anon-ISDN compatible TE and MT. Typically this reference point supports astandard serial interface. Um Interface between the mobile station (MS)and the GSM fixed network part. The Um interface is the GSM networkinterface for providing GPRS services over the radio to the MS. The MTpart of the MS is used to access the GPRS services in GSM through thisinterface. Uu Interface between the mobile station (MS) and the UMTSfixed network part. The Uu interface is the UMTS network interface forproviding GPRS services over the radio to the MS. The MT part of the MSis used to access the GPRS services in UMTS through this interface.

1) method for in a packet switched (PS) core network (CN) supportingseveral quality of services levels, comprising at least a serving node(SGSN), a gateway node (GGSN), a home location register (HLR), a shortmessage service gateway and interworking unit (SMS-GMSC, SMS-IWMSC),charging gateway functionality (CGF), and a public data network (PDN)comprising an application server (AS), the core network being adaptedfor carrying out at least a mobile initiated packet data protocol (PDP)context activation in which a PDP address is assigned to a mobilestation and in which a given quality of service is assigned through thenetwork in a communication session between the mobile station and theapplication processor in question,characterised in that the applicationserver (AS) initiates a context activation in which a requested QoS(Qulity of Service) is communicated: 2) Method according to claim 1,whereby the application server (AS) sends by a Short Message Service(SMS) message the requested QoS class directly to the mobile station(MS), which in turn starts the PDP context activation procedure. 3)Method according to claim 1, whereby the application server (AS)communicates the requested QoS class to the GGSN. 4) Method according toclaim 3, whereby the application server communicates the requested QoSclass to the GGSN according in a push request. 5) Method according toclaim 3, whereby the application server (AS) communicates the requestedQoS class to the GGSN directly in the sent PDU. 6) Method according toclaim 2, whereby the SMS message causes the mobile station to issue aPDP activate context request with the requested QoS class. 7) Methodaccording to claim 2, whereby the SMS message causes the mobile stationto issue a modify PDP context request with the requested QoS class. 8)Method according to claim 2, whereby the SMS message causes the mobilestation to issue an activate secondary PDP context request with therequested QoS class.